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Water Management

Gutter Size Calculator

Determine the correct gutter capacity for your roof in real-time based on square footage and local rainfall.

SQ FT

Why size matters?

Undersized gutters lead to foundation damage, basement flooding, and fascia rot. Correct sizing ensures your roof drainage system can handle peak Utah thunderstorms.

Recommended Gutter Size

5" (Standard)

Min. Downspouts

1

"Standard 5-inch gutters are sufficient for most residential applications in Utah."

* Standard downspout spacing: 1 per 20-30 feet of gutter.

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How to Choose the Right Gutter Size

Selecting the correct gutter size is critical for protecting your home's foundation, siding, and landscaping. While 5-inch K-style gutters are the standard for most residential homes, larger roofs or areas with intense rainfall often require 6-inch or even 7-inch systems to prevent overflow.

Our gutter size calculator uses your roof's square footage and local rainfall intensity to determine the required capacity. A roof that is steeper will also collect and shed water faster, effectively increasing the "water-shedding area" that your gutters must handle.

Key Factors in Gutter Sizing:

  • Roof Square Footage: The total surface area that collects rainwater.
  • Roof Pitch: Steeper roofs accelerate water runoff, requiring deeper gutters or more downspouts.
  • Rainfall Intensity: Calculated based on the maximum 5-minute rainfall intensity for your specific Utah region.
  • Downspout Capacity: The size and frequency of downspouts are just as important as the gutter width itself.

Frequently Asked Questions

When should I upgrade to 6-inch gutters?

You should consider 6-inch gutters if you have a very large roof area, a complex roof with many valleys that concentrate water, or if you've experienced overflowing with standard 5-inch gutters during heavy Utah thunderstorms.

How many downspouts do I need?

The general rule is one downspout for every 20 to 30 feet of guttering. However, for larger 6-inch gutters, you can sometimes space them further, though more downspouts are always better for fast drainage.

Does gutter material affect sizing?

Not directly, but seamless aluminum is the preferred choice for both 5-inch and 6-inch systems due to its durability and lack of leak-prone seams.

How to use calculator results the right way

Every roofing calculator on this site is meant to give you a planning number, not a final contract price. Real roofing scopes change when a contractor verifies the roof geometry, checks how many layers need tear-off, looks at ventilation, and confirms whether flashing, skylights, gutters, or decking repairs are part of the work.

The best use of these tools is to narrow your range before you request an estimate. Once you know whether you are closer to a repair, a replacement, or a ventilation problem, you can compare bids with a much stronger understanding of the variables that actually move price and scope.

What usually changes the final number

  • Actual roof complexity, especially valleys, dormers, transitions, and steep sections.
  • Existing roof condition, including soft decking, old flashing, ventilation defects, or previous patchwork.
  • Material availability, manufacturer requirements, permit needs, and cleanup/disposal costs.
  • Whether the project includes related work like gutters, skylights, insulation, or storm documentation.